Over recent years, there has been a surge in the installation of backyard pools. These pools take the form of either inground or an aboveground type of construction. In either type of construction, the pool owner must periodically test the pool water to insure that the water has the proper chemical balance. This periodic check involves testing the water for its acidity or alkalinity which hereinafter is called its pH characteristic. This test is important since an incorrect pH can be responsible for staining or scaling of the pool's walls or the corrosion of metal accessories, such as pumps, ladders, grab rails, etc.
In addition to the pH characteristic, the pool owner must also make sure that there is enough chlorine in the water to maintain water purity. The clorine level of the pool water is affected by a number of factors such as water temperature, evaporation, rain, the number of bathers, etc.
The stability of chlorine in the pool water and its microbicidal activity are pH dependent. Lower pH values cause a more rapid loss of chlorine, thereby increasing the operating cost of the pool. Higher pH values, on the other hand, retard the microbicidal activity of the chlorine even though tests may show its presence in the water.
Since a proper balance of chlorine in the water is essential to kill bacteria and since pH strongly influences this balance, the pH characteristic must not be allowed to change excessively. Therefore, the pool owner must regularly and accurately check the pool water for its acidity, alkalinity and chlorine content.
There are several known prior art fluid sampling devices. For example, U.S. Pat. No. 1,108,561 to Erickson, issued Aug. 25, 1914, discloses a fluid sampling device consisting of an open cup or receptacle adapted to be inserted into a fluid with a scale disposed in proper relation to the cup. In addition, the device has a piston operating in the cup with a plunger operated by the operator's finger with an indicator acting in conjunction with the scale. The device thus permits taking samples in proportion to the quantity of liquid delivered. The device does not provide for simultaneously taking water samples for pH testing and chlorine testing by color comparison.
Carpinello, in U.S. Pat. No. 2,004,568 issued June 11, 1938, discloses another liquid sampling device which is adapted to take samples of liquids at different depths simultaneously. This device does not provide for simultaneously taking samples for pH testing and chlorine testing by color comparison.
Losee in U.S. Pat. No. 2,236,063 issued Mar. 25, 1941, discloses a dipper for taking samples of liquid to facilitate transfer of the sample liquid from the liquid to be tested. The liquid is then transfered to a test tube in which the sample is tested. This device does not provide for simultaneously taking two samples.
Thomson, U.S. Pat. No. 2,624,201 issued Jan. 6, 1953, discloses an elongated rod and holder for an individual liquid sample container such as a test tube. The device releasably holds the test tube at an adjacent one end so that the test tube can be dipped into the liquid in a bulk container to take a sample therefrom. The filled test tube can then be readily removed from the handle and holder device and replaced by an empty test tube for taking a sample from another container.
U.S. Pat. No. 3,692,490 to Hall, issued Sept. 19, 1972, discloses a pool tester which simultaneously withdraws into two separate containers predetermined samples from a given depth in the pool. As the samples of pool water are drawn into the containers, it injects into each sample a given amount of different testing reagent and ejects the water samples tested from each container after the test results are observed. The tester has an extendible handle which, at one end, includes an elongated rectangular housing having a rounded or arcuate side having cylindrical openings. A pair of cylinders are slidably arranged to extend through the top plate into the cylindrical openings. The cylinders are closed at their upper ends by corks or plugs. The lower end of each cylindrical opening is opened to the outside of the housing by ports. Metering blocks are integrally arranged and the lower ends of the cylinders are divided with metering openings. When the sample is to be withdrawn, the cylinders are moved outwardly of the openings in the housing so as to unseat a ball valve thus permitting water to enter into the openings and to inject the reagents into the openings. Thus, the tester dispenses agents from its cylinders in order to sample the fluid to be tested.
The sampling devices to Losee and Thomson are unsatisfactory for pool testing, in that, these testers are unable to withdraw a predetermined amount from a given depth in the pool. On the other hand, the sampling device of Erickson does not permit the simultaneous withdrawing into two separate containers of predetermined quantities of water from a given depth in the pool. Therefore, the Erickson device is not suitable for testing samples of pool water. The liquid sampling devices of Carpinello and Hall, on the other hand, are complex and expensive to make.